Adjustable escapement mechanism for typewriters



July 14, 1953 F. J. KAVANAUGH ADJUSIABLE ESCAPEIIENT IIECHANISI FORTYPEIRITERS Filed Sept. .26. 1950 V I Jzaerzibr H4230 JHVMZG:

Patented July 14, 1953 ADJ USTABLEESCAPEMENT MECHANISM FOR TYPEWRITERSFloyd J. Kavanaugh, Galveston, Tex., assignor to R. C. Allen BusinessMachines, Inc., Grand Rapids, Mich., a corporation of MichiganApplication September 26, 1950, Serial No. 186,781

6 Claims.

The present invention relates in general to 1 rection of characteromission errors by enabling the operator of the typewriter to easilyerase and rewrite words, or character sequences, from which a letter orcharacter has accidentally been omitted, the mechanism being adjustableto allow the complete correct character sequence or word to be rewrittenin offset relationship in the space previously occupied by the erroneouscharacter sequence, after erasure thereof.

Another important object of the invention is to provide a mechanismwhereby characters normall may be written or impressed successively, inside by side spaced relationship, on a character receiving sheet, and,by adjustment of the mechanism, characters may be written or impressedon the sheet in offset relationship with respect to the position of suchnormally applied characters; a further object being to provide mechanismadjustable to apply characters successively on a receiving sheet inoffset relationship, displaced with respect to normally appliedcharacters by one half of the normal spacement of the normally appliedcharacters.

Another important object is to provide a typewriter having escapementmechanism including an escapement wheel and cooperating shiftable dogmeans for determining the spacement of characters successively appliedon a character receiving sheet, including means for adjusting the dogmeans at will, in the direction of rotation of the escapement wheel,between a normal operating position and a shifted position, so thatcharacters applied on the sheet by the mechanism, when the dog means isin such shifted position, will be offset with respect to charactersapplied to the sheet by operation of the mechanism with the dog means innormal operating position.

The foregoing and other important objects, ad vantages and inherentfunctions of the invention will become apparent as the same is morefully understood from the following description, which, taken with theaccompanying drawings, discloses a preferred embodiment of theinvention.

Referring to the drawings:

Fig. 1 is a perspective view of typewriter escapement mechanismembodying the present invention; and

Figs. 2 and 3 are sectional views taken substantially along the line2--2 in Fig. 1 and respectively showing the parts in position for normaland for offset operation of the typewriter.

Typing errors, involving the omission of a type character in a word orseries of characters, are normally corrected by first erasing the: wordor character series in which the omission has occurred, then backspacingthe character receiving sheet carriage of the typewriter to the erasedspace, and finally inserting each letter of the correct series, inposition oifset one half of the normal character spacement, by holdingthe carriage successively in position While successively applying theseveral characters of the correct character sequence. This is a somewhatslow and awkward procedure.

The present invention contemplates the provision of means operativelyassociated with the escapement mechanism and instantly adjustable as bymanipulation of a convenient control button or handle to condition theescapement mechanism so that the typewriter may be operated either innormal fashion to apply characters on the carriage mounted characterreceiving sheet, or in adjusted position to apply characters on thesheet in offset relationship therein with respect to characters normallyapplied.

To illustrate the invention the drawings show a typewriter escapementmechanism II for causing the character receiving sheet carriage of thetypewriter to shift in step by step fashion either in response to theoperation of a spacing bar or upon actuation of a type bar.

The escapement mechanism comprises a toothed escapement wheel I2drivingly connected with a pinion iii, the wheel and pinion being suitably journaled in the frame of the typewriter. The pinion is formed fordriving engagement with a rack I4 which is fixed on the shiftable typereceiving sheet carriage of the typewriter, which travels in thedirection indicated by the arrow in Fig. 1 under the control of theescapement mechanism, such movement being preferably accomplished byspring actuated tension means of the sort commonly provided intypewriter mechanism, or by any other suitable means.

The tendency of the escapement wheel l2 to rotate under the influence ofthe tension means is controlled in the illustrated embodiment byescapement mechanism l5 comprising a frame is pivotally supported forrocking movement on 7 an axis parallel with respect to the plane of thewheel I 2, the frame being so mounted on pivot pins [1, which preferablycomprise axial extensions on threaded mounting plugs l8 supported in theframe of the typewriter. The frame 16 carries an escapement dog [9 fastthereon, and a dog 20 shiftably mounted on the frame [6. The wheel [2 isprovided with circumferentially plane of the Wheel, spring meansnormally urging said dog means axially in one direction, and adjustablecam means for holding said dog means against the influence of saidspring means in any selected one of a plurality of adjusted positionslongitudinally of said axis.

4. A typewriter escapement mechanism comprising an escapement wheeldrivingly connected with a character receiving sheet carriage, dog meansrockable transversely of the escapement Wheel on an axis parallel withrespect to the plane of the wheel, spring means normally urging said dogmeans axially in one direction, support means for holding said dog meansagainst the influence of said spring means, and manually operable cammeans for adjusting said support means into any selected one of aplurality of adjusted positions longitudinally of said axis.

5. A typewriter escapement mechanism comprising an escapement wheeldrivingly connected with a character receiving sheet carriage, dog meansrockable transversely of the escapement wheel on an axis parallel withrespect to the plane of the wheel, spring means normally urging said dogmeans axially in one direction, a longitudinally shiftable bar formingsupport means for holding said dog means against the influence of saidspring means in any selected one of a plurality of adjusted positionslongitudinally of said axis, and manually operable means for shiftingsaid bar and for holding the same in any selected one of a plurality ofadjusted positions longitudinally of said axis.

6. A typewriter escapement mechanism'comprising an escapement wheeldrivingly connected with a'character receiving sheet carriage, dog

means rockable transversely of the escapement wheel on an axis parallelwith respect to the plane of the wheel, spring means normally urgingsaid dog means axially in one direction, a longitudinally shiftable barforming support means for holding said dog means against the influenceof said spring means in any selected one of a plurality of adjustedpositions longitudinally of said axis, a manually shiftable member, andcooperating cam means on said bar and member for shifting the bar inresponse to operation of the member and for holding the bar in anyselected one of a plurality of adjusted positions longitudinally of saidaxis.

FLOYD J. KAVANAUGH.

References Cited in the file of this patent UNITED STATES PATENTS Number

